Drawing of three congenital malformations leading to an obstruction of the upper urinary tract.
Obstructive uropathies belong to the most frequent malformations of the urogenital organs and are therefore important differential diagnoses of the urinary tract infection and reflux mainly in boys.
On the left side a ureteropelvic junction obstruction is visible; pelvis and calices are dilated.
In the middle there is a juxtavesical ureter stenosis; in addition to the pelvis nearly the whole ureter is dilated. This malformation is somewhat less frequent.
On the right side a ureterocele can be seen; the cele lies in the lumen of the bladder like a balloon, or in the bladder neck, or in the urethra in case of ectopically situated orifice.
The orifice lies always completely at the lower end of the ureter and does not allow
a simultaneous reflux, or is sometimes combined with a reflux.